Muffler.



D. F. LEARY.

MUFFLER.

APPLICATION FILED SEPT 23. I9I6.

1 ,276,935. Patented Aug. 27, I918.

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UNITED STATES DENNIS FRANCIS LEARY, OF CHELSEA, MASSACHUSETTS.

MUFFLER.

Application filed September 23, 1916.

To all whom it may concern:

Be it known that I. DENNIS FRANCIS LEARY, a citizen of the United States, and a resident of the city of Chelsea, in the county of Suffolk, and Commonwealth of Massachusetts, have invented certain new and useful Improvements in Mufliers, of which the following is a full, clear, and exact specifi cation.

This invention is in the line of devices for deadening the exhaust from the engines of automobiles, power boats and the like, and it relates to certain details of construction by means of which the muffler is rendered more efficient in operation and economical in construction.

In the drawings forming, part of this specification, Figure 1 is a central longitudinal section of a muffler embodying my improvements. Fig. 2 is a cross section thereof on the line XX in Fig. 1. Fig. 3 is a cross section on the line Y-Y in Fig. 1. Fig. 4 is a face view, with parts broken .away, of the propelling fan of the mufiler. Fig. 5 is a perspective view of one of the blades of the fan. Fig. 6 is a face view of the-current maintaining fan. Fig. 7 is an edge view of one of the blades of the latter.

The muffler case comprises a sheet metal cylinder 1 having a water-tight jacket 2 spaced about it, with suitable intakes and out-takes 3, 4 for giving a circulation of water through the annular space and thereby cooling the cylinder 1.

The exhaust from the engine enters the cylinder, preferably at its midlength. as shown in Fig. 1, through the pipe 5 which opens tangentially into thecylinder, as shown in Fig. 2; and directly in the line of the enterin exhaust are the fans 6 of a fan wheel which is fixed upon the rotatableaxially disposed shaft 9, and which is forcibly rotated by the inrushing exhaust.

At the ends of the cylinder 1 are the outlets 10 for the exhaust, and intermediate of these outlets and the fan 7 are other fans 11 mounted on the shaft 9 and hence rotated by the power communicated to the fan wheel 7.

At other points in the cylinder 1 are lo cated transverse partitions 12 formed with openings through them preferably near their peripheries, as at 13.

The fan wheel 7 is preferably made in the following way: Two sheet metal disks 14 have hubs 15 punched therein, and peripheral notches 16 and several holes 17, 18.

Specification of Letters Patent. Patented Aug. 27, 1918.

Serial No. 121,873.

Each fan blade 6 has an extension 19 bent at an oblique angle therefrom, but slightly narrower, as shown in Fig. 5, and formed with lugs or spurs 20, 21. The blades are put between the disks, with the inner ends of each blade entering the notches 16; the spurs 20 passing through the holes 17, and the spurs 21 passing through the holes 18. These spurs are then bent over against the outer surfaces of the disks, and said parts are thereby firmly fastened together.

The fans 11 are each composed of a single circular piece of sheet metal, having its center punched up to form a hub 22, and numerous radial slits cut therein to make the blades 28. Each blade is given a twist and a double curve such as shown in Fig. 7, for the purpose hereinafterv set forth.

The operation of the muffler is as follows: As the exhaust intermittently enters the cylinder 1 through the pipe 5, and impinges upon the fan blades 6, the fan and shaft and the fans 11 are set into swift rotation. The exhaust gases then separate laterally to seek their only escape through the outlets 10, and must first pass through the openings 13 in the partitions 12. This somewhat retards the velocity of the escaping gases, and in addition brings them close to the inner-surface of the cylinder 1, which, being refrigerated by the water jacket, reduces the temperature and consequently the volume of the gases, and so diminishes the intensity of their exit.

At the moment that each blast of the exhaust strikes the fan wheel 7, theprevious blast has reached each fan 11 in a retarded condition, and is retarded by the fan 11, and urged somewhat back toward the inlet and fan wheel. This acts as a brake upon the fan wheel, and a further interference with the escape of the gases, but enough gets past between the peripheries of the fans 11 and the cylinder, as well as through the fans themselves, to maintain a sufficient exhaust of the gases, but the interference is such that, with the action of the partitions and of the water jacket, the'gases issue from the exits 10 is a practically uniform and noiseless stream.

Inspection of Fig. 1 and of the inclination of the blades of the fans 11 will show this backward action'given to the gases.

The function of the'extensions 19 in the fan wheel 7 is togive the latter a blast-re ceiving pocket nearer the periphery of the wheel than would be the case Without the extensions, and a consequently 'more effective utilization of the power of each blast.

The action of the double curve given to the blades 23 is two-fold: The edge receiv ing the blast is bent somewhat more nearly to a sharply acute angle therewith in order better to receive the same, while the opposite edge is similarly bent in order to give a more forcible parting impetus to the outgoing gases.

What I claim is:

1. A mufller comprising an elongated chamber having baffler partitions transversely disposed therein, means for delivering exhaust gases into the muffler at one section thereof and for-permitting its escape at another section, a rotative device adapted to be revolved by the inrush of the said exhaust, and a second rotative device revolved by the first one, the second rotative device being disposed in the path of the exhaust as it escapes and being adapted for giving a backward impulse to the passing exhaust.

2. A muffler comprising an elongated chamber having bafiler partitions therein. a longitudinally disposed shaft rotatably supported in the chamber, a fan wheel havin vanes in the same planes with the shaft and fixed on the latter, a fan of the propeller type fixed on the shaft and spaced from the fan wheel, and means for operatively delivering exhaust gases against the vanes of the fan wheel and for permitting their escape past the propeller fan, the latter having blades inclined to resist the gases forced past them.

3. A muflier comprising a chamber adapted to receive exhaust gases, a shaft rotatably supported therein, a fan wheel fixed on the shaft to be rotated by the entering gases, and a fan fixed on the shaft spaced from the fan wheel, said fan having obliquely disposed blades each given a double curvature transversely.

In testimony that I claim the foregoing invention, I have hereunto set my hand this 12 day of September, 1916.

DENNIS FRANCIS LEARY. 

